1. Field of the Invention
This invention relates to a method of manufacturing gel candles, and in particular, to an improved method of manufacturing gel candles having less rigid, non-metal core wicks that stand upright and are not bent, wilted, or submerged in the body of the gel candle.
2. The Related Art
In this modern age of electricity, candles are no longer employed as principal sources of light, but instead are used more for ornamental, decorative, or personal reasons. The candle making art, therefore, has developed a wide variety of candle types to satisfy and fulfill consumer preferences and desires. One such candle type is the gel candle. Gel candles have gained widespread popularity in recent years, perhaps due in large part to the aesthetic appeal of transparent or translucent gels, which can be housed in containers of various shapes, sizes, and designs.
Gel candles are typically made according to a two stage process: a batch stage in which a gel-forming liquid composition is prepared in a batch (i.e., a container or vessel), followed by a continuous filling stage in which candle containers are filled with the gel-forming liquid composition from the batch. As used herein, "gel-forming liquid composition" generally refers to any colloidal dispersion that transforms into a gel state upon cooling, and "gel state" or "gel" generally refers to a colloidal dispersion that has attained a structure that prevents the dispersion from flowing.
The batch stage consists generally of heating and mixing starting materials of a gel-forming liquid composition suitable for use in forming candles in a batch at relatively high temperatures, typically about 250.degree. F. or higher, until a homogeneous, gel-forming liquid composition is formed. The temperature of the gel-forming liquid composition is then lowered to between about 195.degree. F. and about 230.degree. F., and maintained within this temperature range in the batch throughout the filling stage, to prevent gellation of the composition itself in the batch.
FIG. 1 generally depicts the filling stage currently employed in the manufacture of gel candles. Referring to this figure, a wick-clip 12 having a metal core wick 13 is first placed in a candle container 11. As used herein, "metal core wick" means a wick having a metal core, such as zinc, surrounded by cotton or paper fibers; whereas the term "non-metal core wick" means either a wick having a paper or cotton core surrounded by cotton or paper fibers, a cotton fiber wick, a paper fiber wick, or an equivalent. Although most wicks have a microcrystalline wax coating as an outermost coating, such a coating is not necessarily required for gel candles. A magnet (not shown) located underneath container 11 may be used to center wick-clip 12 on the bottom of the container 11.
A gel-forming liquid composition (not shown) is then dispensed into container 11 containing wick-clip 12 and metal core wick 13. As discussed above, the gel-forming liquid composition is usually at an elevated temperature, typically at least between about 195.degree. F. and about 230.degree. F., when dispensed into the container 11. Thereafter, the composition in the container is cooled to form a gel candle.
The preferred practice has been to use metal core wicks in gel candles, because such wicks are capable of withstanding the high temperatures during the filling process. Non-metal core wicks have generally not been used, because they have a strong tendency to bend or wilt in high temperature mediums, thereby resulting in gel candles with off-centered or submerged wicks. Off-centered wicks can lead to cracking of the candle container during burning, due to the closer proximity of the flame to the container wall.
Several drawbacks, however, are associated with using metal core wicks in gel candles. By definition, a metal core wick is a rigid wick, and therefore, burns in a mostly vertical direction in the coldest, center region of the flame. As used herein, "rigid wick" is synonymous with a metal core wick; whereas "less rigid wick" is synonymous with a non-metal core wick. Burning of wicks in the coldest regions of the flame leads to three specific problems. First, a smaller flame size results, which can be aesthetically unpleasing. Second, undesirable-looking charred portions of the wick fall into the liquid pool of gel that forms around the burning wick, due to the incomplete burning of the wick in the coldest regions of the flame. Third, these charred portions sometimes can accumulate around the wick throughout the candle life, resulting in a pile of charred wick portions capable of flaring up and/or creating excessive heat during the last hours of candle usage. These charred portions are also aesthetically unpleasing.
Non-metal core wicks avoid the drawbacks associated with metal core wicks, because non-metal core wicks, being less rigid, bend into the hotter parts of the flame during burning. However, as mentioned above, current gel candle manufacturing processes result in non-metal core wicks being bent, wilted, or submerged in gel candle bodies. Although this problem could be resolved to an extent on a small scale if the wick were physically held in the proper place, this solution is not feasible if gel candles are being mass-produced.
U.S. Pat. No. 5,578,089 (the '089 patent) relates to clear gel candle compositions. The '089 patent briefly discusses a method of making gel candles and mentions generally that a wick is placed in a candle body before the gel firms up. This patent, however, does not disclose or suggest how to produce a gel candle containing a non-metal core wick that is not bent, wilted, or submerged in the candle body.
It is desirable, therefore, to produce a gel candle having a non-metal core wick that stands upright in the candle body. By standing upright, we mean that the wick is located in substantial alignment with a longitudinal axis running through the candle container. Preferably, the longitudinal axis runs through the center of the candle container.